Method for feeding tobacco in a machine for manufacturing tobacco products

ABSTRACT

In a cigarette maker, shredded tobacco passes through a feed and transport section toward a unit by which divided particles of the tobacco are gathered into at least one stream providing the filler for cigarettes. By positioning one or more sensors either along the feed and transport section or at a point upstream, relative to the feed direction of the tobacco, it becomes possible to identify the type of tobacco being handled at any given moment, so that when production schedules include a changeover from one brand to another, supervisors can be certain that the right type of tobacco has been selected, and ensure that different types of tobacco will not mingle.

BACKGROUND OF THE INVENTION

The present invention relates to a unit and a method for feeding tobaccoin a machine by which tobacco products are manufactured.

The invention finds application to advantage in the art field ofcomplete lines for the manufacture of tobacco products, and inparticular cigarettes.

In a conventional line for manufacturing tobacco products, shreddedtobacco passes along one or more ducts from a primary processing sectioninto the feed and transport section of a cigarette maker; a partialvacuum is generated in the ducts, drawing the tobacco first into aheader chamber, then from the header chamber into a feed chamber. Thetobacco is directed en masse from the feed chamber into a carding unitand thereafter into a descending duct, or chute. Emerging at the bottomof the chute, the tobacco is transferred toward the bottom end of anascending duct or chimney, enclosed at the top end by at least onemoving conveyor consisting in an air-permeable aspirating belt by whichthe tobacco, drawn up through the chimney as a continuous flow ofdistinct particles, is attracted and gathered progressively into acontinuous stream.

Externally of the chimney, the stream of tobacco advances from theaspirating belt toward the entry point of a station where it isfashioned into a continuous cigarette rod; the continuous rod will thenbe cut into single cigarette sticks, which are transferred to a filtertip attachment machine.

The schedules of a single manufacturing facility, and indeed of singleproduction lines operating within the facility, each composed typicallyof a cigarette maker, a filter tip attachment machine and one or morecigarette packers, will normally include frequent changes of theparticular brand in production, as dictated by demand. A change of brandmeans generally that the type of tobacco, the cigarette paper, tippingpapers and filter tips, and the packet and carton blanks used for thenew brand will be different to those in use previously.

Having shut off the supply of tobacco and paper to the cigarette maker,the machine itself is kept in operation until all the cigarette stickshave run out, followed by the final length of cigarette rod still in theprocess of being formed.

Once the machine has been emptied, an operator will proceed to changethe type or blend of tobacco and, if envisaged, the type of paper usedto wrap the rod, the tipping papers, and the filters.

Once the tobacco has been changed, the line can be started up again.

It will often become clear when the machine has already produced acertain quantity of cigarettes, for example from systems monitoring thequality of the single cigarettes turned out, that the tobacco isunsuitable and the product must be discarded, incurring considerableloss of time and materials. The error in question is frequentlyattributable to the fact that different types of tobacco can often be sosimilar in color as to be indistinguishable to the eye of an operator.

In addition, even when the change of tobacco has been accomplishedwithout error, it is inevitable that traces of the tobacco usedpreviously will remain in the cigarette maker, especially in the chuteof the feed and transport unit, and mingle with the new tobacco.Likewise in this instance, a certain quantity of cigarettes must bediscarded.

The object of the present invention is to provide a tobacco feed unit ina machine for manufacturing tobacco products, such as will be unaffectedby the aforementioned drawbacks.

One object of the invention, in particular, aimed at minimizing theimpact attributable to a change of brand in a machine for manufacturingtobacco products, is to provide a tobacco feed unit that will allow ofverifying the selection of a certain type of tobacco and/or preventingdifferent types of tobacco from becoming mingled in production.

Similarly, the object of the present invention is to provide a method offeeding tobacco in a machine for manufacturing tobacco products, such aswill be unaffected by the aforementioned drawbacks.

A further object of the invention, in particular, aimed at minimizingthe impact of a change of brand in a machine for manufacturing tobaccoproducts, is to provide a method of feeding tobacco that will allow ofverifying the selection of a certain type of tobacco and/or preventingdifferent types of tobacco from becoming mingled in production.

SUMMARY OF THE INVENTION

The stated objects are realized in a tobacco feed unit according to thepresent invention, applicable to a machine for manufacturing tobaccoproducts, comprising means by which shredded tobacco is fed along apredetermined path toward a unit of the machine where tobacco particlesare formed into a continuous stream, and sensing means deployed alongthe predetermined path, by which the tobacco is identified according totype before it reaches the forming unit.

The aforementioned objects are realized similarly in a method of feedingtobacco in a machine for manufacturing tobacco products, including thesteps of shutting down the machine to suspend production of a firstbrand of tobacco product made from a first type of tobacco, replacingthe first type of tobacco with a second type of tobacco used tomanufacture a second brand of tobacco product, and activating sensors toidentify the type of tobacco being handled by the machine beforeinitiating production of the second brand of tobacco product.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail, by way of example, withthe aid of the accompanying drawings, in which:

FIG. 1 is a perspective view showing a cigarette maker and part of atobacco feed unit according to the present invention;

FIG. 2 is a schematic representation of the tobacco feed unit in FIG. 1,shown enlarged and in its entirety.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, numeral 1 denotes a machine, in its entirety,for manufacturing tobacco products 2 such as cigarettes, by way ofexample.

The machine, or cigarette maker 1, is equipped at the upstream end witha tobacco feed and transport section 3 by which a mass of shreddedtobacco 4 is formed into a continuous flow of tobacco particles. Thecomponents of the feed and transport section 3 are housed in avertically extending enclosure 5 delimited uppermost by a horizontalwall 6 and on either side by two vertical walls 7.

Shredded tobacco 4 is directed into at least one header chamber 11surmounting the horizontal wall 6 and connected by way of at least oneinlet duct 12 to a primary processing section denoted 13, shownschematically in FIG. 2. Leaf tobacco fed into this same section 13 isprocessed and conveyed by pneumatic means (not illustrated) along theduct 12 and into the chamber 11.

The section denoted 3, the inlet duct 12 and the outfeed stage of thesection denoted 13 combine to establish a feed unit 8 that serves todirect the tobacco 4 along a predetermined path extending from theupstream section 13 toward a downstream unit 9 by which it is formedinto a continuous stream 10.

The header chamber 11 connects on one side with a carding unit 14 towhich it supplies the tobacco 4, and is equipped internally with amovable wall 11 a such as can be operated intermittently to open andclose the passage to the carding unit 14.

The carding unit 14 comprises a power driven feed roller, denoted 15, bywhich the shredded tobacco 4 is directed down into a lower chamber 16delimited at the bottom by a conveyor belt 17.

The chamber 16 houses a carding drum or roller, denoted 18, rotatableabout an axis 18 a transverse to the two side walls 7 and occupying aposition adjacent to the downstream end of the belt 17.

In addition to the carding roller 18, the unit 14 comprises aproportioning roller 19 set in rotation substantially tangential to thecarding roller 18 and in the same direction.

With this arrangement, the shredded tobacco 4 can be directed by thefeed roller 15 onto the belt 17 and then toward the carding roller 18,whereupon a layer of the shredded tobacco 4 substantially equal inthickness to the radial dimension of the carding teeth is transferred bythe roller 18 away from the chamber 16 and beyond its positiontangential to the proportioning roller 19.

Also associated with the carding unit 14 is an impeller roller 20rotatable about an axis parallel to the axis 18 a of the carding roller18, of which the function is to take up the layer of tobacco 4 from thissame roller 18 and shower the constituent particles, in the directiondenoted F1, down into a substantially vertical descending duct or chute21 delimited by a pair of side walls 22 set parallel one with anotherand with the axis 18 a of the carding roller 18.

The bottom end of the chute 21 is located facing the periphery of atransport device 23 by which the tobacco 4 is conveyed from this samebottom end of the chute 21 toward the bottom end of an ascending duct orchimney 24, of which the top end connects with the unit 9 forming thecontinuous stream 10 of tobacco 4.

In the example illustrated, the aforementioned transport device 23comprises a take-up roller 26 and an impeller roller 27 combining totransfer the shredded tobacco 4 away from the chute 21.

The take-up roller 26 is designed to project the tobacco 4 in the formof distinct particles onto a transport belt 28 moving from right to leftas seen in FIG. 2, and angled upward with the runout end located beneaththe inlet of the chimney 24.

In an alternative embodiment of the invention (not illustrated), thetransport belt 28 could be replaced by a fluidized bed, of conventionaltype, consisting in a static surface extending between the chute 21 andthe chimney 24, along which the tobacco 4 is caused to slide by a flowof air.

The top outlet end of the chimney 24 is enclosed by two aspirating belts29 of the aforementioned unit 9, on which particles of tobacco collectand are formed gradually into relative streams 10 that will be fashionedultimately into cigarettes 2.

Each stream 10 of tobacco is advanced together with a strip 30 of paperdecoiling from a roll 31 and directed along a path passing through aprint device 32, thence toward a garniture assembly 33 by which thestrip 30 is draped around the stream 10 of tobacco to form a continuouscigarette rod 34. Whilst the invention is described with reference to adual rod, twin-track type cigarette-making line, it will findapplication advantageously just the same in a single rod, one-track typeline.

Each rod 34 advances toward a cutting station 35 at which it is dividedby a rotary cutter device 36 into discrete cigarette sticks 37 ofpredetermined constant length, and more exactly, twice the length of astick forming part of a single cigarette 2.

The cut sticks 37 are transferred to a filter tip attachment machinedenoted M, not illustrated in detail, being conventional in embodiment.

The tobacco feed unit 8 further comprises sensing means 38 able toidentify the type of tobacco 4 being handled by the feed and transportsection 3, before it reaches the unit 9 by which the particles areformed into stream 10. Such sensing means 38 operate along thepredetermined path leading from the outfeed of the primary processingsection 13 to the unit 9, that is to say, by way of the inlet duct 12,the header chamber 11 and carding unit 14, the descending duct or chute21, the transport device 23 and the ascending duct or chimney 24.

The sensing means 38 in question comprise at least one sensor 39 mountedin close proximity to the predetermined path and preferably at pointswhere the tobacco 4 tends to accumulate, so as to maximize the responseof the sensor 39.

The sensors 39 are wired to a central processing unit, or CPU 40, bywhich signals are received from the selfsame sensors 39 and comparedwith stored parameters relative to different types of tobacco 4 in sucha way as to provide a data item identifying the tobacco 4 advancingcurrently through the feed and transport section 3.

The sensors 39 adopted would be of conventional olfactory type, forexample, capable of detecting gaseous substances given off by thetobacco 4 and peculiar to each variety or blend. Such sensors usesemiconducting metal oxide thin film technology, and when heated totemperatures of 300-400° C. will register a thermal conductivitydetermined by the gases to which they are exposed.

Alternatively, use could be made of infrared sensors, likewiseconventional, which measure the extent to which the tobacco 4 absorbspredetermined frequencies in the infrared range, the rate of absorptionbeing dependent on the presence and percentages of certain substances inthe tobacco 4. The parameters stored in the CPU 4 are packets ofinformation relative to the spectral absorption of each type of tobacco.

The accompanying drawings illustrate a plurality of sensors 39 placed atvarious points of the feed unit 8. In practice, all of these or onlycertain of them might be included.

One or more sensors 39 can be installed upstream of the carding unit 14,considered relative to the flow of tobacco 4 advancing along thepredetermined path aforementioned, so as to identify a new type oftobacco 4 at the infeed stage before an entirely new production run isbegun by the machine 1, as explained below. The sensor 39 in questioncould be placed at any given point along the inside of the inlet duct12, for example immediately downstream of the primary processing section13, or upstream of the inlet duct 12 and at the outfeed stage of thissame section 13, or immediately upstream of the header chamber 11, orpreferably, in the header chamber 11 itself.

Alternatively, or in addition to the sensors 39 placed upstream of thecarding unit 14, sensors 39 could also be positioned downstream of thecarding unit 14, for example in the chute 21, along the transport device23 or in the chimney 24, of which the function would be to verify thatthe cigarette maker 1 has been emptied correctly and entirely ofmaterial from the previous run. Given that these sensors 39 are bestlocated at points where the tobacco 4 tends to accumulate, as explainedabove, and in particular when the machine 1 is shut down during achangeover from one brand to another, the optimum locations will be inthe chute 21 and, if installed, in the fluidized bed (not illustrated).

The brand changeover procedure involves shutting down both the cigarettemaker 1 and the downstream filter tip attachment machine M, so as tosuspend the production of a first brand of cigarettes 2 manufacturedfrom a first type of tobacco 4 and using other brand-specific materials,such as the cigarette paper, filter tips, filter papers and possibly thetypes of ink and gum.

In particular, adopting the method of feeding tobacco 4 according to thepresent invention, the flow of the first type of tobacco 4 is suspendedat the primary processing section 13, as also is the supply of paper 30from the rolls 31, whereas the cigarette maker 1 continues operating inorder to use up the tobacco 4 still occupying the carding unit 14, atleast in part, and cause the remainder of the cigarette rod 34 stillbeing formed in the garniture assembly 33 to run out of the machine.

Once the cigarette maker 1 has been shut down, clean-up systems ofconventional type will come into operation to clear the more easilyaccessed parts of the machine, albeit residual amounts of shreddedtobacco will inevitably remain in the carding unit 14, and particularlyin the chute 21, above the take-up roller 26.

The tobacco 4 occupying the primary processing section 13 is replacedwith a second type or blend, or alternatively, the entire section 13 isreplaced with another section 13 containing the second type of tobacco4. If envisaged, similarly, the paper 31 utilized for the cigarette rod34 will be replaced, likewise the ink in the print device 32 and the gumsolutions.

Before commencing a new production run with a second brand of cigarette2, the sensing means 38 are activated so as to verify the type oftobacco 4 passing through the feed and transport section 3.

In a first test cycle, determined by a relative software program andimplemented by the CPU 40, the wall 11 a of the header chamber 11 isclosed off so that new tobacco 4 of the second type cannot pass into thecarding unit 14, and pneumatic means are activated by the CPU 40 todirect a predetermined quantity of the new tobacco 4 from the processingsection 13 into the header chamber 11.

Once a sufficient quantity of the tobacco 4 has collected in the chamber11 or in the duct 12, the sensor or sensors 39 placed upstream of thecarding unit 14 are activated to run a spot check, effected in a matterof seconds, or tenths of a second, and serving to ensure that thetobacco 4 is indeed of the correct type. Accordingly, the CPU 40processes the signal received from the sensor 39 to obtain a valueindicating the type of tobacco 4 effectively contained in the headerchamber 11 and compares this same value with a reference parameterentered by the operator and corresponding to the second type of tobacco4 used in the new brand. If the tobacco 4 detected is that of the newbrand, the CPU 40 responds by initiating the new production run, eitherautomatically or when enabled by the operator; conversely, if thetobacco is not of the right type, the CPU 40 will output an error signalby means of a conventional indication system.

Alternatively, or in parallel with the first test cycle, the cigarettemaker 1 may run a second test cycle, likewise implemented by the CPU 40,with the aid of the sensors 39 positioned downstream of the carding unit14.

In the second cycle, the sensor or sensors 39 placed downstream of thecarding unit 14, located preferably within the chute 21 immediatelyabove the take-up roller 23, will identify the type of tobacco 4 beforeand/or immediately after the cigarette maker 1 is started up, so as toensure that the first type has been entirely used up. Only afterverifying that there are no longer any traces of the first type oftobacco 4, or that the tobacco present is the right type, will the CPU40 respond by initiating the new production run, automatically or whenenabled by the operator.

It would also be possible, likewise in accordance with the feed methoddisclosed, for the CPU 40 to establish initially which type of tobacco 4is in the chute 21 and thereafter, once the cigarette maker 1 has beenrestarted and running for a short interval, take a second readinginternally of the chute 21 to ensure that the tobacco in the cardingunit 14 is in effect only of the second type.

The objects stated at the outset are realized by the unit and the methodaccording to the present invention, and the drawbacks associated withthe prior art thus overcome.

In effect, with sensing means 38 deployed along the predetermined feedpath, it becomes possible to make certain that the correct type oftobacco 4 has been selected and ensure that different types of tobaccowill not mingle when changing over from one brand to another on a singlecigarette making line.

In particular, the first test cycle implemented using sensors 39 placedupstream of the carding unit 14 serves as a preliminary sample test onthe tobacco 4 about to be fed into the system.

Furthermore, the second test cycle implemented with the aid of sensors39 placed downstream of the carding unit 14 serves to verify whether ornot there is still any trace of the tobacco 4 in use previously, atpoints where accumulation is more likely to occur, so that theappropriate measures can be taken before initiating the new productionrun.

1-13. (canceled)
 14. A method of feeding tobacco in a machine formanufacturing tobacco products as in claim 13, including the steps of:shutting down the machine to suspend production of a first brand oftobacco product made from a first type of tobacco; replacing the firsttype of tobacco with a second type of tobacco from which to manufacturea second brand of tobacco product; activating sensing means in order toidentify the type of tobacco being handled by the machine beforeinitiating production of the second brand of tobacco product.
 15. Amethod as in claim 14, including the further steps of closing off theheader chamber to prevent the second type of tobacco from flowing intothe carding unit, feeding a predetermined quantity of the second type oftobacco into the header chamber by way of the inlet duct, and activatingsensing means deployed upstream of the carding unit for an interval oftime sufficient to identify the type of the new tobacco.
 16. A method asin claim 14, including the step of emptying the machine of the firsttype of tobacco, wherein the step of activating the sensing meansconsists in activating at least one sensor placed downstream of thecarding unit for an interval of time sufficient to verify that there isno trace of the first type of tobacco in the machine before initiatingproduction of the second brand of tobacco product.